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CVE-2026-64267

Estado: AnalizadaMedia (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

fuse: avoid 32-bit prune notification count wrap

FUSE_NOTIFY_PRUNE validates the nodeid payload length with:

On 32-bit kernels, size_t is also 32 bits, so the daemon-controlled count multiplication can wrap. A prune notification with count 0x20000000 and no nodeid payload passes the check, enters the copy loop, and asks the device copy path to read nodeids that are not present in the userspace write buffer. In QEMU this reaches the fuse_copy_fill() BUG_ON(!err) path.

Validate the payload length with array_size() instead. That accepts exactly the same valid messages, but avoids wrapping arithmetic before the copy loop consumes the count.

Detalles técnicos trazas, registros y código del informe original
    size - sizeof(outarg) != outarg.count * sizeof(u64)

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-64267",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3f29d59e92a96d843c2ff10ebfed92ac26878658",
              "lessThan": "6e2d84fdeac05bfd858e84a76353fdb84f23a43e",
              "versionType": "git"
            },
            {
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              "versionType": "git"
            },
            {
              "status": "affected",
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              "lessThan": "54243797cedf55447b4c5d560e8cd709900061ae",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/fuse/dev.c",
            "fs/fuse/notify.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.18",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/fuse/dev.c",
            "fs/fuse/notify.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-07-25T10:17:06.910",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/54243797cedf55447b4c5d560e8cd709900061ae",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6e2d84fdeac05bfd858e84a76353fdb84f23a43e",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c78c4b242299bc581e4987e5c2786c6f4760c516",
      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfuse: avoid 32-bit prune notification count wrap\n\nFUSE_NOTIFY_PRUNE validates the nodeid payload length with:\n\n    size - sizeof(outarg) != outarg.count * sizeof(u64)\n\nOn 32-bit kernels, size_t is also 32 bits, so the daemon-controlled\ncount multiplication can wrap.  A prune notification with count\n0x20000000 and no nodeid payload passes the check, enters the copy\nloop, and asks the device copy path to read nodeids that are not\npresent in the userspace write buffer.  In QEMU this reaches the\nfuse_copy_fill() BUG_ON(!err) path.\n\nValidate the payload length with array_size() instead.  That accepts\nexactly the same valid messages, but avoids wrapping arithmetic before\nthe copy loop consumes the count."
    }
  ],
  "lastModified": "2026-08-17T05:17:25.547",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CA2CE3BD-0548-4984-8C39-F3D3DF4D64E1",
              "versionEndExcluding": "6.18.39",
              "versionStartIncluding": "6.18"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6228DDD6-4557-4AA3-9F43-AB995D471E42",
              "versionEndExcluding": "7.1.4",
              "versionStartIncluding": "6.19"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}